ODYNERUS. 183 



unique bordering of the first segment, although certain females 

 pussess a second band like the males; b}' its obscure face; by its 

 slender form, by its abdomen which is not briefly sessile, and the 

 thickness of the border of the first segment of the abdomen, which 

 causes the 2d segment to appear so subcompressed at its base. 

 See the 0. campestris, to which it is closely allied. 



Sab. The United States. Connecticut. Illinois. Iowa. 

 Prairies (Rio Pecos). Tennessee. North Carolina. 10 ?; 12 %. 



Observation. — Among the dried specimens one generally finds 

 the abdomen extremely swelled, as if the segments had been 

 violently distended. This peculiarity belongs especially to this 

 species and gives it an unusual appearance. 



25. A. campestris Sauss. — Niger, grosse punctata ; metanoti foveola 

 baud acute margin ita, inermi, striata et grosse punctata; abdominis 

 segmentorum 2'-5' margine rugose punctato ; anteimis subtus fulvis, 

 scapo flavo-liueato ; elypeo 9 fiavo, macula atra, % emarginato, flavo ; 

 puncto frontali et post-oculari, prouoti et abd. segmentorum V-3" limbo 

 (primi utrinque aucto), post-scutello, maculis 2 scutelli maculaque sub- 

 alari, tibiis et tarsis, tiavis ; alis fusco-uebulosis. 

 Odynerus campestris Sadss. Vespides, I, 137, 18 ; III, 204, £, . 

 9 . Total length, 13 mm. ; wing, 11 mm. 



9. Head and thorax cribrose with great pits, quite visible to 

 the naked eye. Clypeus pyriform, as wide as long, cribrose with 

 great punctures; its anterior border small, bordered, subconcave, 

 upon the vertex often a little fossette. Prothorax unarmed, finely 

 bordered. Mesothorax marked with two grooves; scutel flat; 

 post-scutel short, sloping. Metathorax rounded, rugose; its con- 

 cavity pronounced, but not limited; divided by a vertical carina 

 which bifurcates at the summit to form two arcs which indistinctly 

 border the cavity at the summit ; the middle and the bottom of 

 the concavity wrinkled; the summit coarsely punctured. Abdo- 

 men ovalo-conic, punctured ; the first segment large, almost as 

 wide as the 2d; borders of the segments 2-5 presenting a wide 

 coarsely punctured zone, rugose, but not turned up ; the border 

 of 2d segment sinuous, forming a concave arc. 



Insect black, clothed with a grayish pile. Antennae ferrugi- 

 nous beneath. Clypeus yellow, with a triangular black spot. 

 A line on the scape of the antennae, a spot on the front, one 

 behind each eye, border of the prothorax, a spot beneatn the 

 wing, wing scales, two dots on the scutel, post-scutel, and a 



